Paper container



R. S. SANFORD PAPER CONTAINER Nov. 21, 1950 Filed Dec. 6, 1945 Unven ior Roy S. Scugfordi attorneys,

Patented Nov. 21, 1950 Roy S. Sanford, akville,Conn., assignor, by me'sne assignments, of one-half to Ex-Cell-O Corporation, Detroit, Mich, a corporation of Michigan, and one-half to a group comprising Ace C. Fessenden, Chicago, Ill., and Ace Carton Corporation, Chicago, 11]., a corporation of Illinois Application December 6, 1945, Serial No. 633,218

8 Claims. (Cl. 229-55) This invention relates to containers oipaper or other sheet material and more particularly to 'a novel means and method for sealing the end of such containers in order to provide a liquidtight or sift-proof receptacle for liquid or powdered materials.

Heretofore, many attempts have been made to devise a liquid-tight or sift-proof paper board receptacle, of the type wherein one or both ends thereof are provided with superimposed ,fiaps which are adhesively secured together. Such paper receptacles have not, however, met with a high degree of success, due partly to the particular manner in which sealing of the flaps has been attempted, and partly to the factthat the prior methods were highly expensive and were not well suited or adaptable for efficient and economical use at the point of filling the receptacles. One of the serious problems in devices of this character resides in the difllculty of completely sealing all pin holes and cracks which are inherently present in all paperboard containers of the type having a rectangular cross section and wherein the end or ends are formed with folding flaps. This problem is not so serious where an inner lining is provided, as in the case of packaged powdered material. However, the problem is rather acute when attempts are made to employ an unlined receptacle for liquids, such as milk, for example, as well as for powdered materials. Various elaborate and expensive arrangements have been proposed for providing the desired liquid-tightness. For the most part, such arrangements utilize a small amount of adhesive to secure or bond the flaps together, and have relied upon an interior coating of wax to plug the holes and cracks, but the utilizing of such a method necessitates the installation of special machinery for providing the wax coating. Moreover, such a coating does not possess the required tensile strength, and it has been found in practice that should the receptacle be subjected to jars and shocks, or be dropped, the portion or the coating relied upon for sealing the holes and cracks will break away, and leakage of the liquid will result.

One of the objects of the present invention is to accordingly provide a novel means and method for sealing the end of a paperboard container and particularly a container of the type having 9. rectangular cross section.

Another object resides in' providing a novel sealing means and method for paper containers of the above character wherein the ends of the container are provided with one or more: flaps,

which in the case of a plurality of flaps, are

adapted to be arranged in superposed relation.

Still another object comprehends a novel methodand product produced thereby, for efflciently seallng all of the pin holes and cracks which may be present in the end of a container of the above type, after the flaps are folded together. such method avoiding the necessity of utilizing complicated and expensive machinery.

Another object is to provide a novel arrangement for sealing the container end, wherein an adhesive interposed between a plurality of flaps which latter may be integral or separate from the container, is caused to positively flow to the pin holes and cracks, under the application of pressure applied to the flaps, the arrangement being such, that when the adhesive sets, it becomes in eil'ect, an integral portion of the mate- .rial of the container so that the container may withstand severe jars and shocks without danger of leaking.

, Yet another object is to provide a novel arrangement for sealing the container end, so constituted that an adhesive coating of uniform thickness may be applied to the end flaps of the container, and caused to flow under pressure to seal the pin holes and cracks.

Still another object comprehends the use of different types of flaps or closure panels for the end of the container which are coated with an adhesive and thereafter firmly pressed together for the purpose of positively flowing the adhesive outwardly to the container walls for the efiicient sealing of all pin holes and cracks which might be present in the container end.

A further object resides in the provision of a novel means and method of the above character, which is highly efficient in operation, yet relatively simple and economical to perform, and which is especially adaptable for use at the point where the containers are to be filled.

Other objects and novel features of the invention will appear more fully hereinafter from a consideration of the following detailed description when considered in connection with the accompanying drawing, wherein several embodiments of the invention are illustrated. It is to be expressly understood, however, that the drawing is utilized for purposes of illustration only, and is not to be taken as a definition of the limits of the invention, reference being had for this latter purpose to the appended claims.

In the drawing, wherein similar reference characters refer to similar parts throughout the several views:

Fig. 1 is an axial sectional view of a container constructed in accordance with the present invention and employing a pair of end fiaps or panels which are separate from the container walls:

Fig. 2 is an axial sectional view of a modified form of the invention utilizing a pair of end flaps, one of which is formed integrally with a wall of the container, while the other is separate therefrom;

Fig. 3 is a partial perspective view of still another form of the invention wherein four fiaps which areintegral with the container walls are utilized;

Fig. 4 is a partial perspective view of the end of the container of Fig. 3, showing the flaps in sealed position. and

Fig. 5 is a sectional view of the container of Fig. 4 taken substantially along line 5-5 thereof.

The present invention, in one of its broad aspects comprises the application of pressure on opposite sides of two or more superposed flaps or panels, which form one end of the container, the flaps being coated with an adhesive which is caused to positively flow in all directions in response to the applied pressure, and to not only secure the flaps together, but also to effectively seal all of the pin holes and cracks which may be present in said end. A further aspect resides in the employment of an adhesive which, after it sets or dries, possesses a tensile strength which is substantially equal to that of the paper board of which the container is formed. This latter feature is especially important and desirable where the container is used for liquids. In the event that the container is used for light-weight powdered material and a sift-proof construction is desired, the adhesive need not have a tensile strength as high as that indicated.

Referring more particularly to Fig. 1, the novel method of the present invention is illustrated therein as being applied to an open ended container ill having a substantially rectangular cross section. The container ill is preferably of the well-known type which may be supplied by the manufacturer in a flattened, knocked-down condition and provided'with a side seam 12, Fig. 3, which is firmly sealed by any suitable adhesive. In view of the fiat condition of the containers, the latter may be readily shipped to the point where the containers are to be filled, and may be set up by conventional machinery preparatory to treatment in accordance with the present invention.

In order to provide a sealed end for the container Ill, the present invention, as shown in Fig. 1, contemplates the employment of a pair of end flaps or panels I! and i6, which are separate from the container and which are of such size as to fit snugly within the open end of the latter. One or both of the adjacent faces of flaps I4 and I! are coated with a suitable adhesive IS, in any suitable manner, and are thereafter assembled in the open end of the container ill, with the flaps in superposed relation as shown in Fig. 1. A suitable support or base 20 is employed for supporting the above mentioned parts, following which a ram or plunger 22 having a cross section substantially of the same shape as that of the container I 0 is forced downwardly against the upper face of flap H to firmly compress the sandwich constituted by the flaps I4 and i6 and the interposed layer of adhesive It. The pressure which the plunger exerts upon the flaps is increased to the point where, as shown in Fig, l,

the adhesive is is caused to positively flow outwardly to the side walls of the container, and to firmly adhere thereto, such pressure being preferably maintained until the adhesive sets or dries. It will be readily understood that with such an arrangement, the flowing adhesive forms a pair of upper and lower continuous bands 24 and 26 which are respectively interposed between the edges of the flaps l4 and I8 and the interior surface of the container, while being integral with the layer I8 between the flaps. Such bands completely seal all of the cracks around the edges of the flaps l4 and i6 and thus provide, with the said flaps, a liquid-tight end for the container. As shown, the support or base 20 is 'cupshaped and thus provides a support engaging the exterior surfaces of the side walls of the container adjacent the flaps l4 and I6. Hence, such side walls are prevented from moving outwardly in a direction at right angles to the vertical axis of the container in response to the pressure of the adhesive as the latter is positively flowed into contact with the inner surfaces of the walls. In this manner, the adhesive is positively forced against the inner surfaces of the side walls to not only form a continuous sealing band between the free edges of the flapsand the container walls to provide a leak-proof joint, but also to firmly bond the edges of the flaps directly to the container walls.

In the form shown in Fig. 2, instead of having both of the flaps or panels i4 and is separate from the container l0, only one flap I4 is separate while the flap is is formed integrally with one of the side walls of the container. With such an arrangement, the crack along one edge of the flap it, where the latter is joined to the container wall is eliminated and the lower adhesive band 26 is also eliminated along this edge. In all other respects, the method for compressing the sandwich comprising flaps I4 and i6 and the adhesive layer l8, and for securing the novel sealed end construction, is precisely the same as in Fig. 1, it being understood that the upper adhesive band 24 securely joins all of the edges of the flap H to the container walls, while the lower adhesive band 26 which extends around three of the sides of the fiap it effectively secures the latter to the container walls. Thus all pin holes and cracks are entirely eliminated and a liquid-tight construction is assured.

The present invention may be practiced with other types of flaps other than those shown in Figs-1 and 2. For example in Figs. 3, 4 and 5, the invention is illustrated in connection with a container having a pair of full-size flaps 22 and 30 and a pair of half-size flaps 22 and 34, all of the flaps being formed integrally with the container walls. In this form of the invention, the inner surfaces of each of the flaps 20, 32 and 34 are coated with a layer 36 of the adhesive, in any suitable manner, following which the flaps 28, 30, 32 and 34 are folded down in the order named to position free edges of flaps 28 and 30 within the container as shown in Fig. 5, and the container is placed in the recessed support 20, as in Figs. 1 and 2. Thereafter, pressure is applied to the sandwich comprising the flaps and adhesive layers, by means of the plunger 22, whereupon the adhesive layers 36 are caused to flow outwardly to completely fill and seal the pin holes located at the four corners of the end of the container. As in the case of Figs. 1 and 2, the flowing adhesive will cause the formation of the upper and lower adhesive bands 24 and 26 which .will extend around the free edges of each of the flaps 2t and ll, see Fig. 5. It will be understood that the function of the recessed support 2|, in connection with the formation of the end closure of Figs. 3, 4, and 5. is the same as that previously described in connection with Fig. 1.: Preferably, in order to secure the advantageous results set forth above, the coating of the adhesive, which may be of uniform thickness if desired. covers the entire surface of the respective panel or panels to which it is applied, and the thickness of such coating or coatings is such that the amount of the adhesive is in excess of that required to merely seal or bond the panels together. Thus, by this arrangement, a supply of adhesive for sealing purposes is assured, it being understood from the foregoing, that upon the application of pressure, the excess adhesive is positively flowed outwardly to the adjacent walls of the container in order to completely seal all of the cracks and openings in the container end.

Following the assembly of the container end in the manner heretofore described, it will be understood that in all of the modifications a firm and secure bond is secured between the end flaps, and simultaneously therewith, a thorough and eflioient plugging and sealing of all pin holes and cracks is secured for rendering the container completely liquid-tight, in the case of liquids, and sift-proof in the case of powders. In the former case, it is preferable to employ and adhesive, which when in a set condition, possesses a tensile strength substantially the same as the paper of the container, thus materially contributing to the strength of the sealed end. In actual practice, it has been found that in using an adhesive having the foregoing strength, it is impossible to separate the flaps, after the adhesive has set, without tearing the paper. Thus the invention provides a substantia ly integral end structure of greater strength than those heretofore provided. If desired, the interior of the container may thereafter be coated with a suitable wax or plastic composition for the purpose of moisture-proofing.

It will be readily apparent from the above that the present invention provides a novel method for quickly and efficiently sealing the end of a paperboard container to render the same liquidtight or sift-proof and to also secure an end of exceeding strength which is well adapted to withstand severe jars and shocks without leaking. Such desirable results are achieved by the proposed sandwich construction comprising two or more flaps with interposed layers of adhesive, together with the use of pressure to cause a positive outward flow of the adhesive for effective joining of the flaps together as well as a complete sealing and closing of all pin holes and cracks which may be present by reason of the particular flap construction. The invention is well adapted for bottling milk in dairies, for example, since the containers may be shipped in a flattened, knocked-down condition and may be readily set up and sealed without the use of complicated or expensive machinery.

It will be observed that the container end, resulting from the present invention, is flat and that no projecting flanges, beads or ribs are utilized. Such an arrangement provides maximum strength while avoiding the use of false bottoms or tops which increase the overall height of the container for a given capacity.

while several embodiments of the invention have been shown and described herein with con- 6 slderable particularity, it will be understood that the invention is not limited thereto but may be embodied in various forms. For example, if it is desired to employ a thermoplastic type of adhesive, it will be understood that suitable heating means may be associated with the plunger 22 and the base 20, and in such event, subsequent cooling of the compressed flaps and plastic adhesive may be utilized for setting the latter. Such an arrangement is especially desirable where the containers are to be assembled and sealed at the filling plant. Whatever type of adhesive is employed, however, one of the essential requirements thereof must be in the ability to flow under the application of pressure, in order to achieve the desired contact with the container walls for sealing all cracks and openings. In addition to the foregoing, different arrangements of the end flaps may be employed, as for example. structures having only a pair of opposed full size flaps with or without the addition of a separate flap or panel, all or some of these having adhesive coatings thereon to provide the sandwich construction which is compressed to cause a flowing of the adhesive to secure the flaps together and achieve the sealing of all openings. Various other changes and modifications may be resorted to, as will readily appear to those skilled in the art without departing from the scope of the invention. Reference will therefore be had to the appended claims for a definition of the limits of the invention.

What is claimed is:

1. The method of sealing an open end of a paper board container having a plurality of side walls arranged to provide a polygonal cross section which comprises coating with a flowable adhesive a plurality of panels, said panels when overlapped forming a closure for said open end, overlapping said coated panels at said open end in superposed relation to close the open end of the container, at least a pair of said plurality of panels being positioned within the container, and subjecting one face of said superposed panels to pressure of a value sufficient to flow the adhesive outwardly to contact the walls of the container to seal all openings and cracks and to bond at least said pair of panels directly to the container walls, and to bond all of said panels together while simultaneously supporting the other face of the panels over the entire area thereof, and simultaneously supporting the exterior walls of the container adjacent the panels against movement outwardly in a direction at right angles to the vertical axis of the container in response to the pressure exerted by the outwardly flowing adhesive.

2. The method of sealing an open end of a container having a plurality of side walls ar- 1 ranged to provide a rectangular cross section which comprises assembling a plurality of panels in superposed relation to provide a flat end closure for said open end, said panels having a flowable adhesive coating therebetween and at least one of the panels having a shape conforming to the cross section of the container and being assembled within the container, supporting the exterior walls of the container adjacent the panels against movement-outwardly in a direction at right angles to the vertical axis of the container while positively compressing the opposite faces of the superposed panels together over the entire faces thereof to a value suflicient to ositively flow the adhesive outwardly to contact the supported container walls to seal all open- 7 lugs and cracks and to bond the free edges of at least one panel to the supported container walls and to bond the panels together.

3. The method of making a container having an open end and a plurality of side walls arranged to provide a rectangular cross section which comprises coating with a fiowable adhesive a plurality of flat panels having a rectangular shape, and at least one of the panels having a shape conforming to the cross section of the container, overlapping said coated panels in superposed relation to close the open end of the container to provide a flat end closure therefor with said one panel within the container, supporting the exterior walls of the container adjacent the panels against movement outwardly in a direction at right angles to the vertical axis Y of the container while positively compressing the opposite faces of the superposed panels together over the entire faces thereof to a value suflicient to flow the adhesive outwardly to directly contact the inner surfaces of the supported container walls to seal all openings and cracks between the free edges of at least one panel and the inner surfaces of the supported container walls to securely bond said free edges directly.

to said inner surfaces and to bond the panels together, and thereafter coating said container with wax to render the same moisture proof.

4. The method of making a container having an open end and a plurality of side walls arranged to provide a rectangular cross section from a fiat paper board blank having four wall panels, two of said panels being provided with integral end closing full flaps, and the other two panels being provided with integral end closing half flaps which comprises coating some of said flaps with a thermoplastic adhesive capable of flowing under the application of heat and pressure, overlapping said flaps to provide a flat closure for said open end and to bring some of the free edgesof some of the flaps closely adjacent the inner surfaces of the container side walls, supporting the exterior walls of the container adjacent the flaps against movement outwardly in a direction at right angles to the vertical axis of the container while positively ap- 8 plying heat and pressure to the opposite faces of the overlapped flaps to positively flow the adhesive outwardly to directly contact the inner surfaces of the supported container walls to seal all openings and cracks between said free edges and said inner surfaces of the container side walls to firmly bond said free edges directly to said inner surfaces and to firmly bond the flaps together, and thereafter coating said container with a wax composition to render the same moisture proof.

5. As a new article of manufacture, a container produced in accordance with the method set forth in claim 1.

6. As a new article of manufacture, a container produced in accordance with the method set forth in claim 2.

7. Asa new article of manufacture, a container produced in accordance with the method set forth in claim 3.

8. As a new article of manufacture, a container produced in accordance with the method set forth in claim 4.

ROY s. SANFORD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 809,812 Kimsey Jan. 9, 1906 1,215,464 Armstrong Feb. 13, 1917 1,393,413 Wallertz Oct. 11, 1921 1,397,756 Drysdale Nov. 22, 1921 1,711,642' Hulbert May 7, 1929 1,881,375 Ristow Oct. 4, 1932 1,976,980 Bergstein Oct. 16, 1934 2,073,415 Enkur Mar. 9, 1937 2,140,178 Wesselman Dec. 13, 1938 2,335,865 Lanigan et a1 Dec. 7, 1943 2,341,845 Mark at all Feb. 15, 1944 2,471,307 Carvalho May 24, 1949 FOREIGN PATENTS Number Country Date 443,252 Great Britain Feb. 25, 1936 

